In 2015, according to a study by the Radicati Group, over 205 billion emails were sent and received worldwide each day. There were also about 2.58 billion email users and 4.53 billion emails in existence that same year.

Like every other internet-based product/service, email has brought with it its own share of advantages and drawbacks (most of which weirdly are a result of its laudable efficiency). In truth, however, email is not the problem; it is the way we use it that can cause a drop in our overall performance and productivity at work.

Here are some mistakes we make with email that cause us to underperform:

1. Not using a unified email system

Many of us have more than one email account, from different email service providers. It is bad enough that emails ambush us every day from all corners without our having to switch constantly between email accounts to follow up on these messages. Doing this only takes time run away from our work, so we end the day having achieved less.

What to do: Consider using an all-inclusive email platform on your mobile and desktop, such as the Outlook app; this helps you keep track of your emails, from one source. It is a more efficient way to deal with email correspondence without burning yourself out. You can also have separate email accounts for business, personal use and any other reason.. This is a way to keep unimportant emails out of sight and consequently, out of mind.

What makes this scenario worse is that it takes time to get back to full concentration -- 64 seconds on average, according to a Loughborough University study -- away from the task you were handling before. With every email interruption, this time suck easily builds up to a sizable chunk of time wasted daily.

What to do: Instead of being carried away by email interruptions, map out a time in your daily schedule to check email. Also, adjust your settings to notify you of any new email activity every few hours instead of every five minutes.

3. Using email when other communication channels would serve better

Email as a messaging (not chatting) platform is great; however, it is addictive and can easily lull us into using it for reasons it was not created for. If you want to schedule a meeting with your team of 15 by email, you may quickly find yourself entangled in a long chain of messages that will make your decision-making process more tedious than necessary.

In that context,, we may find ourselves using email for everything. But that only serves to keep our focus away from the work we should be doing.

What to do: If you need your assistant or any other member of your staff, simply call out to that person or put a call through to his or her workstation. If you need to set up a meeting with some investors or members of your team, do that with a call (voice or video), not with email.

Just make sure you do not default to email for everything; this could lower your productivity.

4. Overusing the CC feature

The basic idea of the "cc" feature is to keep people in the loop. Some of us, however, feel the need to go into a cc'ing frenzy, so we copy any and everyone we can, including staff who have nothing to do with the subject of the email. Worse still is the fact that those people you copy on an email are copied by default on the responses to that email, too: You just end up having staff hate your emails and dread any notification that comes in.

Every email has to be opened, read, processed mentally and acted upon. So, while you think you are just keeping everyone in the loop, you may just be creating blocks of time when your employees are distracted from their core responsibilities.

What to do: There is no point cc'ing more members of staff than is necessary. Generally, you should cc someone only if you want him or her to do something with the email you are sending; otherwise don't bother.